The invention relates to a drum cleaner for cleaning a coiler furnace drum such as a drum of the type found in coiler furnaces for use with Steckel mills (reversing rolling mills).
A Steckel mill is one of the various types of rolling mill commonly installed in a production line for the manufacture of steel plate or strip. A Steckel mill is typically used to roll the steel (so as to reduce the thickness of the steel) while the steel is at a desired (typically relatively high) temperature so as to produce a desired steel microstructure. As such rolling reduction typically requires more than one pass (and sometimes several passes) through the Steckel mill, coiler furnaces are typically installed in line with the Steckel mill (one coiler furnace upstream of the Steckel mill and a second downstream of the Steckel mill) to maintain the temperature of the steel between passes through the Steckel mill. A coiler furnace has an internal rotatable generally-cylindrical drum. The leading edge (for the time being) of coilable plate or strip emerging from the Steckel mill that requires further passes through the Steckel mill is directed into the nearer coiler furnace and wound onto its drum. Subsequently, the plate or strip is unwound from the drum as it is fed back through the Steckel mill for a further pass. Sometimes, steel is temporarily kept coiled in the coiler furnace while other operations are in progress and then uncoiled and sent downstream on the production line or, if further rolling in the Steckel mill is required, after the next pass it is wound onto the drum of a coiler furnace on the other side of the Steckel mill.
During use, the work surface of the coiler furnace drum (that is, that portion of the coiler furnace drum that contacts the plate or strip) tends to accumulate unwanted matter such as scale and other debris. It is desirable to remove this unwanted matter from time to time to prevent it from being transferred to, and thus contaminating, the steel plate or strip wound on the drum.
To clean coiler furnace drums, it is conventional practice to hold a scraper (typically a piece of scrap steel) against the periphery of the drum, while the drum is rotated, so as to scrape unwanted matter from the surface of the drum. This procedure is sometimes ineffective and hazardous, and typically may be performed only when the coiler furnace is idle and (depending on the means for holding the scraper against the drum) relatively cool. Coiler furnace housings incorporating pivoting gates with scrapers attached at their distal ends, are also known. With such arrangements, the drum may be cleaned by pivoting the gate so as to bring the scraper into contact with the rotating drum.
Smith (U.S. Pat. No. 5,498,156, issued Mar. 12, 1996) discloses a dual-purpose guide and drum cleaner for coiler furnace winding drums. The guide and drum cleaner functions as a pivoting guide for guiding steel plate or strip into the coiler furnace so as to engage the winding drum and thus be coiled within the coiler furnace. The pivoting guide also functions as a drum cleaner in that it has a drum cleaner element attached at its distal end that can be brought into contact with the rotating drum to rub against the outer cylindrical surface of the drum so as to knock off the unwanted matter clinging to the drum""s surface. Smith discloses two alternative drum cleaner elements, a consumable, abrasive-type cleaning element and a scraper-type cleaning element. When the abrasive or scraper-type cleaning element is worn down, it is replaced with a fresh cleaning element.
Due to uneven wear along their lengths, known drum cleaners typically do not provide even or consistent contact pressure against the drum, and thus do not provide even or consistent cleaning of the drum. Further, with cleaning elements that are attached to gates in the coiler furnace housing or that are part of a guide, the coiler furnace must be shut down and permitted to cool in order to replace worn cleaning elements. What is needed is a coiler drum cleaner that effectively cleans the surface of the coiler drum; that can be used when the coiler drum is at its normal operating temperature; and that permits maintenance and changing of the cleaning element while the coiler furnace is at its normal operating temperature. Such cleaner would be expected to facilitate consistent and uniform removal of debris along the length of the drum and would tend to minimize down time while cleaning is performed.
A coiler furnace drum has a peripheral cylindrical surface and is rotatable. In this specification and in the appended claims:
a) xe2x80x9cwork surfacexe2x80x9d refers to the portion of the peripheral cylindrical surface of the drum that is available for contact with the steel that is wound around the drum when the coiler furnace is in use;
b) xe2x80x9cdrum lengthxe2x80x9d refers to the length of the work surface as measured parallel to the axis of rotation of the drum;
c) xe2x80x9cdrum circumferencexe2x80x9d refers to the circumference of the work surface;
d) xe2x80x9caxialxe2x80x9d and xe2x80x9caxiallyxe2x80x9d refer to a direction or movement substantially parallel to the axis of rotation of the drum; and
e) xe2x80x9cradialxe2x80x9d and xe2x80x9cradiallyxe2x80x9d refer to a direction or movement that is substantially perpendicular to an axial direction.
In accordance with an aspect of the present invention, there is provided a coiler drum cleaner comprising means for moving a cleaning element toward and into close proximity with the work surface, and means for supporting the cleaning element and moving the cleaning element axially, such that during the cleaning operation, the cleaning element may be moved axially so as to bring the cleaning element into contact with different circumferential portions of the work surface. Axial movement of the cleaning element during the cleaning operation compensates for inconsistencies in the cleaning effectiveness of different portions of the cleaning element (due, perhaps, to wear).
The axial length of the cleaning element that in use is engageable with unwanted matter on the work surface for removing the unwanted matter, is preferably less than the drum length (and more preferably no more than about half of the drum length), such that during use, the cleaning element is moved across the work surface of the rotating drum in order to contact and remove unwanted matter from the whole of the work surface. A cleaning element with a length considerably less than the drum length will typically be less costly than a cleaning element with a length equal to or greater than the drum length. As well, a cleaning element with a length considerably less than the drum length will enable more efficient cleaning in that the cleaning action can be localized so as to provide cleaning action for a longer or shorter time period as needed for different portions of the work surface.
The coiler drum cleaner includes means for retractably inserting the cleaning element into the coiler furnace, such that between cleaning operations, the cleaning element may be completely withdrawn from the coiler furnace, so that: the cleaning element does not interfere with the operation of the coiler furnace; the cleaning element is exposed to the high temperatures of the interior of the coiler furnace only for the time required to perform the cleaning operation; and maintenance of the coiler drum cleaner, such as changing or inspecting the cleaning element, may occur while the coiler furnace is operational.
In accordance with an aspect of the present invention, there is provided means for axially retractably inserting the cleaning element into the coiler furnace. In accordance with another aspect of the present invention, the coiler drum cleaner is configured such that the axial movement of the cleaning element for insertion into, and retraction from, the coiler furnace of the cleaning element, is in the same direction of movement as the movement of the cleaning element along the work surface over the drum length during cleaning. In this way, the means for inserting and retracting the cleaning element, and the means for moving the cleaning element axially along the work surface over the drum length, may be one and the same, or may make use of some of the same components.
Preferably, the means for axially retractably inserting the cleaning element and the means for axially moving the cleaning element along the work surface over the drum length, comprise a cleaner frame, in use installed adjacent to the coiler furnace; and a longitudinally-extending cleaning element support member having an insertion end for insertion into the coiler furnace and supporting the cleaning element proximate to the insertion end, the cleaning element support member supported by the cleaner frame and axially displaceable relative to the cleaner frame, wherein, the insertion end of the cleaning element support member and the cleaning element are axially retractably insertable into the coiler furnace by axial displacement of the cleaning element support member relative to the cleaner frame.
Preferably, the cleaning element support member is a rectangular, tubular member, supported by two sets of rollers rotatably mounted on the cleaner frame, such that the cleaning element support member is cantilevered when the insertion end of the cleaning element support member is inserted into the coiler furnace. However, it will be clear that the cleaning element support member need not be rectangular in cross-section and need not be tubular.
Preferably, the cleaning element support member is moved longitudinally with a rack-and-pinion assembly driven by an electric motor, with the rack attached to the cleaning element support member and the electric motor attached to the pinion and mounted on the cleaner frame. It will be clear that other conventional means could be used for moving the cleaning element support member, such as a hydraulic or pneumatic ram, or a worm gear.
Preferably, the means for biasing the cleaning element toward and into closeproximity with the work surface comprises means for radially displacing the cleaning element relative to the cleaning element support member towards the work surface. Alternatively, the means for biasing the cleaning element toward and into close proximity with the work surface could comprise means for moving the insertion end of the cleaning element support member radially towards the work surface. Such means could comprise: means for radially displacing the cleaning element support member relative to the cleaner frame; means for pivoting the cleaning element support member relative to the cleaner frame so as to swing the insertion end of the cleaning element support member towards the work surface; means for radially moving the cleaner frame so as to move both the cleaner frame and the cleaning element support member radially together; and means for pivoting the cleaner frame and the cleaning element support member together.
Preferably, the means for radially displacing the cleaning element relative to the cleaning element support member comprises a carriage, to which the cleaning element is mounted, the carriage being slidably mounted to the cleaning element support member such that the carriage may be reversibly radially displaced relative to the cleaning element support member towards the work surface; and means for radially displacing the carriage relative to the cleaning element support member toward the work surface. Preferably, the means for radially displacing the carriage comprises a reversibly expandible device, such as a pneumatic bag or hydraulic or pneumatic ram, interposed between the carriage and the cleaning element support member, and means for providing pressurized fluid to the expandible device. The means for radially displacing the carriage may be another expandible device, or other conventional means for effecting such relative displacement, such as a rack and pinion, or worm gear.
When the coiler drum cleaner is configured and installed so that the cleaning element is below the drum when inserted into the coiler furnace, then the radial displacement of the carriage towards the work surface will be upwards and gravity may be utilized to move the carriage away from the work surface after the cleaning operation.
Alternatively, for installations where the cleaning element is not below the drum when in use, or additionally, for installations where the cleaning element is below the drum when in use but gravity is not adequate to move the carriage away from the work surface, there may be provided means for causing the carriage to move away from the work surface. Such means may comprise a hydraulic or pneumatic ram attached to both the carriage and the cleaning element support member, so as to be both a means for radially displacing the carriage toward the work surface and a means for moving the carriage away from the work surface. When the means for radially displacing the carriage comprises a pneumatic bag interposed between the carriage and the cleaning element support member, the means for causing the carriage to move away from the work surface may comprise a rocker arm, pivotally mounted to the cleaning element support member. The rocker arm has a linked first end pivotally engaging the carriage and a free second end. A reversibly expandible pneumatic bag is interposed between the second end and the cleaning element support member, wherein, expanding the pneumatic bag causes the rocker arm to pivot so as to move the carriage and cleaning element away from the work surface.
There may also be provided means for adjusting the force with which the cleaning element is held against the drum so as to alter the aggressiveness of the cleaning action of the cleaning element. Such means may comprise a pressure regulating valve for regulating the pressure of the pressurized fluid provided to a pneumatic bag, pneumatic ram or hydraulic ram interposed between the carriage and the cleaning element support member.
It is conceivable that the cleaning element support member be movable for insertion into, and retraction from, the coiler furnace in a direction substantially perpendicular to the axis of rotation of the drum, such that the means for inserting and retracting the cleaning element support member, and the means for biasing the cleaning element against the rotating drum, are one and the same. For example, the cleaning element support member could be configured and positioned for insertion into the coiler furnace through the top of the coiler furnace. However, with such a configuration, the insertion/removal apparatus would have to be installed so as to take up space in the production line (where space is typically limited) rather than installed to the side of the production line.
In accordance with another aspect of the present invention, the cleaning element is configured to be rotated during use; is rotatably mounted to the carriage; and is rotated during the cleaning operation. Preferably, the rotatable cleaning element is a substantially cylindrical brush comprising an array of projecting, resiliently-flexible tines. Preferably, the tines are steel and are carbide-tipped. Preferably, the axis of rotation of the brush is substantially parallel to the axis of rotation of the drum.
Alternatively, the rotatable cleaning element may have an abrasive cylindrical periphery, perhaps made by removably attaching suitable replaceable abrasive material to a reusable core.
In use, it is desirable to position the brush at a selected cleaning position (that is, at a selected radial proximity to the work surface) such that the contact between the tines and the work surface is suitable for effective cleaning of the work surface, but does not subject the tines to undue wear or damage during the cleaning operation. Preferably, the coiler drum cleaner includes a depth guide configured and positioned to contact the drum when the brush is in the selected cleaning position and, when contacting the drum, to impede movement of the cleaning element towards the drum so as to protect the tines. Preferably, the depth guide is mounted to the carriage adjacent to the brush, such that the depth guide moves along the work surface over the drum length with the brush during the cleaning operation. The depth guide may, in use, tend to contact the unwanted matter to be removed from the work surface. Conceivably, as the depth guide rides over such unwanted matter, the depth guide could cause the carriage to move away from the work surface so as to reduce the cleaning effectiveness of the brush. However, in practice, this is not a problem. Generally the thickness of unwanted matter permitted to build up on the work surface is not appreciable, and the slight variations in the contact between the tines and the work surface caused by the depth guide riding over this unwanted matter does not affect the cleaning effectiveness. From time to time the unwanted matter builds to a sufficient thickness that it does reduce the cleaning effectiveness. However, this can be easily dealt with by making more than one pass of the brush over the work surface or over the portion of the work surface with the unusually-thick unwanted matter.
The depth guide may be a wheel, mounted concentric with the axis of rotation of the cleaning element and free to rotate. In this way, when the depth guide is contacting the rotating drum, friction between the depth guide and the drum will cause the depth guide to rotate rather than merely rub against the drum, so as to reduce wear on the portion of the depth guide for the time being in contact with the drum. Two depth guides may be provided, one depth guide located at one end of the rotatable cleaning element and the other depth guide located at the other end of the cleaning element.
The cleaning element may be rotated by an electric motor, also mounted on the cleaning element support member and drivingly coupled to the cleaning element with a drive shaft. Other conventional means for providing rotational drive to the cleaning element may also be used. Preferably, the cleaning element is housed proximate to one end of the cleaning element support member (the cleaning end) and the electric motor (or other means for rotating the cleaning element) is mounted proximate to the other end of the cleaning element support member, such that the electric motor is not inserted into the coiler furnace during the cleaning operation and thus is not exposed to the high temperatures within the coiler furnace. Preferably, the axis of rotation of the cleaning element is substantially parallel to the longitudinal axis of the cleaning element support member, as this configuration permits a relatively simple mechanical coupling, such as a shaft and possibly gears between the cleaning element and the motor driving the cleaning element. However, it will be clear that the axis of rotation of the cleaning element need not be substantially parallel to the longitudinal axis of the cleaning element support member; for example, bevel gears could be used to accommodate an axis of rotation of the cleaning element that is not parallel to the longitudinal axis of the cleaning element support member.
Alternatively, the coiler drum cleaner may comprise two (or possibly more) rotatable cleaning elements, each rotatably mounted in a respective carriage Preferably, the rotatable cleaning elements have similar diameters and are aligned so as share a common axis of rotation; and the carriages are axially spaced. Preferably, each of the carriages is slidably mounted to the cleaning element support member as described above for a single carriage. Alternatively, the two or more rotatable cleaning elements may be rotatably mounted in a single carriage.
Typically, such dual (or multiple) cleaning elements will be designed to provide equally aggressive cleaning from each. For example, where the cleaning elements are brushes, the tines on one brush will be essentially identical to the tines on the other brush. The use of such dual cleaning elements can reduce the time required to clean the drum, in that two cleaning elements will clean more quickly than a single similarly-sized cleaning element. Preferably, both of the dual cleaning elements rotate on one shaft, or the shafts that they rotate on are connected end to end, such that a single means for rotating the cleaning elements, such as an electric motor, may be used to rotate both cleaning elements at the same time and at the same speed.
Alternatively, the cleaning aggressiveness of the dual cleaning elements may be different, one from the other, and the dual cleaning elements may be used sequentially when cleaning the drum, such as for example, where both the cleaning elements are brushes, the tines of one brush may be sharper, harder and/or stiffer for a first aggressive cleaning of the drum surface (such as to remove large particles firmly attached to the drum surface) and the tines of the other brush may be less stiff for less aggressive cleaning (such as to remove smaller particles perhaps missed by the first brush or to polish the drum surface). Such dual cleaning elements having different cleaning aggressiveness may be structured and operated to be rotated at the same speed or at different speeds.
The rotatable cleaning elements or coiler drum cleaners comprising two or more cleaning elements, need not be similar in diameter and need not share the same axis of rotation.
Preferably, there is also provided means for cooling the cleaning element support a trough-like cavity within the cleaning element support member suitable for containing cooling liquid so as to partially submerge the brush. Such cooling means may include a cooling header for showering the cleaning element and adjoining components with water (or other liquid suitable for cooling). Such cooling means may also include channels within the carriage to permit the circulation of water or other liquid suitable for cooling within the carriage. Preferably, such channels in the carriage are connected to ports opening at or adjacent to those surfaces of the carriage that slide against the cleaning element support member, such that these sliding surfaces may be cooled, and possibly partially lubricated, by the water or other liquid. Preferably, there is also provided means for cooling the portions of the cleaning element support member that are, during use, exposed to the high temperatures within the coiler furnace. Such cleaning element support member cooling means may comprise channels in the cleaning element support member for circulating water, other liquid suitable for cooling or air, to be circulated throughout the length of the cleaning element support member. Such channels may be provided by using hollow tubes as longitudinal structural components in the cleaning element support member, as the interiors of such tubes provide ready-made channels. Such cooling header, carriage channels and cleaning element support member cooling means may be in fluid communication, with one another, such that, for example, water may be circulated through channels in the cleaning element support member and thence to the carriage channels and cooling header.
The various features of novelty that characterize the invention are pointed out with more particularity in the claims. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be made to the accompanying drawings and descriptive matter in which there are illustrated and described preferred embodiments of the invention.